As temperatures drop, your preparation has to increase. Whether you"re cycling, jogging, hiking, or doing anything outdoors, if you"re not comfortable then you"re not performing at your best. Our high performance Zirotek fabric (92% polyester/8% spandex) features a familiar spandex exterior shell and a soft, warm fleece interior lining. Engineered after polar bear"s fur, the hollow core design uses filament yarns to trap air and improve thermal insulation. The heat generated is then stored in the hollow core center and is released back to your body to keep you warmer when the weather gets tougher. Additionally, the elastic waistband includes an adjustable drawstring and the ankle zippers make it easier to slip the tights on and off. Bonus features include the reflective material on the ankle zippers and the hidden internal pocket. All tights are made in the USA.